Pipe tong



Aug. 27, 1946. w. w.- WILSON PIPE TONG Filed June 8, 1945 3 Sheets-Sheet1 I Zmnentor: WILL/AM I44 W/zsoxv,

' Gttorneg W. W. WILSON PIPE TONG Aug. 27, 1946.

Filed June 8, 1943 a Sheets-sheaf, 2

I Imnentor: lV/LL/AM H4 W/zsom Gttomeg Aug. 27; 1946. w. w. WILSON PIPETONG f FiledJune 8, 1945 3 Sheets-Sheet Zmnentor:

WILL 1AM 14A W/Lso/Y,

Patented Aug. 27, 1946 UNITED STATES PATENT I OFQFICE PIPE TONG WilliamW. Wilson, Los Angeles, Calif.

Application June 8, 1943, Serial No. 490,007

12 Claims.

This invention relates to tongs of the type used in screwing togetherand unscrewing pipe sections, and particularly to tongs used in oil welldrilling operations where the safe, efficient and rapid operation of thetong is a considerable factor, for example, in the speed with which thepipe is run out of the hole and back in again, in the process ofchanging drill bits.

This application is a continuation-in-part of my copending application,Serial No. 305,350, filed November 20, 1939, for Tong and method ofproducing same.

It is an object of the invention to provide a I tong wherein the jawsare so formed and the pivots are so arranged that ample rotational forceis transmitted by the tong to the held pipe without danger of crimpingthe pipe or producing permanent distortions thereof, and the shearingforces carried through the pins during the use of the tong are nearlybalanced so that one or more pins are not over-stressed while others areunder-stressed.

It is an object of the invention to provide a tong having acharacteristic arrangement of pivots for connecting the jaws, thisarrangement of pivots contributing to or being characteristic of anarticulated jaw arrangement whereby the forces applied to the surface ofthe pipe are substanti lly evenly distributed and proportioned orbalanced so that there is not a heavy concentration of pressure inlocalized areas of the pipe which will result in crushing or crimpingthe pipe when heavy torsional force is transmitted between the tong andthe pipe held thereby. This valuable result is accomplished withoutsacrifice of any ability to transmit ample rotational force through thetong to the pipe and a marked improvement over existing tongs isattained. This valuable result is accomplished by the applicants newspiral arrangement of pins and formation of jaws without sacrifice ofany desirable quality in the tong, but with other improved results suchas the handling of the tong in its normal use by a single operator;whereas, two operators are ordinarily employed in the operation of priorart tongs of comparative size.

It is an object of the invention to provide a tong having rear jaw meansand front jaw means, the rear jaw means having limited movement relativeto the handle, so that the pipe engaging portions of the rear jaw meansmay be readily brought into engagement with the rear side of a pipe inresponse to movement of the handle by a single operator, and the frontjaw means being swingable through a relatively wide are and consistingof at least two jaw members which move toward the operator of the jawswhen they swing into open position, with handle means operable by theoperator to swing the front jaws quicklyaround the front side of thepipe and into engagement with latch means so as to be connected to therear jaw means in operative relation, the entire operation of the jawbeing accomplished by a single operator.

A further. object of the invention is to provide a three-jaw tong havingthe characteristics set forth in the foregoing, wherein three of thepivots are disposed so as to define around the pipe a substantiallyequilateral triangle.

A further object of the invention is to provide a three jaw tong whereinthe balance of clamping forces is made possible by the provision of alon rear jaw, a shorter front jaw and a lug jaw pivotally connected tothe outer end of the short jaw and connected to the outer end of thelong jaw'by latch means, the long jaw having pipe engaging means lyingon a line substantially tangential to the held pipe and passing throughthe. outer pin of the long jaw, this pipe engaging means being disposedrelatively near to the center of the long jaw and moving into engagementwith the surface of the pipe substantially along a radial line whichpasses through the center of the pipe and through a point intermediatethe ends of the pipe engaging means of the long jaw.

It is a further object of the invention to provide a three-jaw tongdevice having therein the Valuable features enumerated hereinbefore,this tong device having a handle with a first jaw pivoted thereon, asecond jaw pivotally connected thereto, and a complement of third jaws,each of a diiferent size, adapted to be separately connected to thesecond jaw, thereby making it possible by changing one part of the tongin use to adapt the tong for a different size of pipe. I am aware of theuse of additive links or jaw members adapted to be insertedin anexisting arrangement of tong jaws to increase the nominal size of thetong, but I have found nowhere a suggestion teaching the herein setforth use of three jaws so arranged that the nominal size of the tongmay be changed by replacing one of the jaws with a jaw of differentsize, in which tong satisfactory gripping of the pipe is obtained andease of handling is achieved in all of the uses of the tong from a rangeof three and one-half inches to over ten inches pipe diameter.

Further objects and advantages of the invention will be brought out inthe following part of the specification.

V Referring to the drawings which are for illustrative purposes only,

tutable for the intermediate jaw of Fig. 1.

Fig. 2 is a side elevation of the tong and hanger. Fig, 3 is a plan viewof the jaw end with the jaws in fully open position. v

' Fig. 4 is a section substantially on line 44 Fig. 3.

Fig. 5 shows in perspective the jaw end of the tong handle with the jawsremoved.

7 Fig. 6 shows the long jaw in perspective. Fig. 7 shows the latch inperspective. Fig. 8 shows the short jaw in perspective. 7 V Fig. 9 showsthe lug jaw in perspective. Fig, 10 is a longitudinal section throughthe latch and the associated end of thelong jaw, Fig. 11 is a plan viewof a spring. Fig. 1111 shows a friction washer in perspective. Fig. .12is an enlarged fragmentary view for pointing out relationships withgreater particularity. Referring first to sheets one and two of thedrawings, the tong comprises the handle which is tapered from its jawcarrying end to its free end and which, for the purpose of lightness andstrength, may be of I-section. At its jaw carrying extremity the handleis provided with a bore 2| and spaced from this bore toward the free endof the handle is a bore 22 defined at both ends by integral collars asat 23, Fig. 5. The axes of the bores lie in a common plane perpendicularto the plane of the handle. The long jaw 24 has a bifurcated end piercedto receive a pintle pin 25, which may be referred to as the working pinor pivot means of the tong, which is passed through the'bore 22. The jaw24 is provided with a stop 26 which cooperates with the stop 21 on thehandle to limit the opening movement of the jaw, as shown in Fig. 3. Atits opposite end, the

jaw 24; is provided with a tongue 28 which has a bore 29 defined at eachend by a collar as at 30, Fig, 6. Near the tongue 28, the jaw 24 isprovided with a handle 3| which extends outwardly so as to beconveniently gripped by the operator;

The jaw 24 is further provided with an inner curvedface 32 into whichare set dies 33 and'34. The curved face 32 is somewhat nearer the tongueend 28'of the jaw than the bifurcated end andbetween the latter and thecurved face, the

jaw is provided with an arcuate recess 35. The latch 35 comprisesparallel bar portions 3! and 38 which are preferably integrally joinedby a cross portion 39 beyond which is formed a stirrup or U-shapedhandle 49. The portion 39.has a preferably fiat latch face 3911. Attheir, free extremities the portions 31 and 38 are pierced to receive apintle pin 4!, parallel to which passes through the bore 29 of thetongue 28. The collars, as at are embraced by substantially U-shapedsprings 42 and 43, whose ends are respectively engaged with abutments 44and 45 on the latch and withan abutment surface 46 on the jaw 24. Thesprings y eldably urge the latch inwardly, their effect being Iimitedbythe engagement of the abutment portions 41 and 48 on the latch and onthe jaw respectively. As shown, the springs 42 and 43 are each made upof. two nested identical components, although if weaker action isdesired, oneof the springs may be omitted or one component of each ofthe springs may be of 'thetong ends ofthese springs bearing againstabutments 5i and 52011 the jaw 24, and abutments 53 and 54 on thehandle, Figs. 1,3, 5, and 6; The springs as attil tend to hold the jaw24 in fully openpo- 1 sition with the abutments 26 and 2? in engagementas shown in Fig. 3. If desired, the springs between the collarssurrounding the bore 22 of the handle'and the overlying portions of thebifurcated end of the jaw 24. Such washers will serve to hold the jawyieldingly in'adjusted positionrelative to the handle. r

The short jaw preferably of the U-section shown in Fig. 4.-,'hasbifurcated ends which are pierced to receive pintles 57 and 58 parallelto the others, of which the former passes through the bore 2% of thehandle and may be referred to as the fulcrum pivot pin or pivot means 51of the tong; The jaw 56 has a curved inner faceSS into which are setdies 60 and 5H. Thisjaw has an abutment surface 62 which cooperates withan abutment portion 63 on the handle to limit opening movement of thejaw, as shown particularly in Fig. 3.

The intermediate or lug jaw 54 has a tongue 65 provided with a bore forthe reception of the pintle 58 by means of which the jaws 56 and 84 arepivoted together. The jaw 54,.has an, outwardly projected handle 63adjacent thepintle 53 and has an inner curved face 6?. At its endopposite the tongue 65, the jaw 64 has a lug 68 with beveled side edgesand a flat face 58a for cooperation with V the face 38a of the latch.Opening movement of the jaw 54- relative to the jaw 56 is limited bymeans of the cooperating abutment portions 68 and as particularly shownin Fig. 3.

The handle 28 is provided with an oblong open-' offset somewhat to theside of the handle ing t: away from the center of gravityX and substantially spaced from the latter. Between the hole 1'! and the pintle 25,the handle isprovided with laterally projecting ears l2 and E3 whoseends are provided with openings. The ear i2 is somewhat nearer the jawend of the handle thanthe ear '53, and the long dimension of the openingH extends on a line 1/ substantially perpendicular to and bisecting theline 2 joining the centers of the ear openings. The ear 13 on the sideof the handle on which the two jaws 56 and 64 are mounted is longer thanthe ear 12 in order to compensate for the greater jaw weight on thatside of the handle. The ear openings are equally spaced at the sides ofthe lines y of lateral balance.

A hanger 14 consists ofa curved web or body portion 15 which at itslower end has a hook formation 56 adapted to be engaged in the opening'1! of the handle. portion constituted by laterally extending ears and'38. having openings equally spaced from the web 15 adapted to registerwith the openings ears l2 and 13 so that the foot portion and the handlemay be connected by a pair of bolts 19 and Bi which supplement the hook16. The foot portion of the hanger is also connected with the bodyportion by a handle portion 8|.

The body portion of the hanger is surmounted With the hanger mounted asshown in Fig. 2, its

upper portion is curved toward the jaw' end of the handle and the headportion 8.2 is inclined downwardly toward the said jaw end.

At its free extremity the handle is provided with hook formations 84 and85 extending above and below the handle back toward the jaw end of thelatter. The extensions and the handle are pierced to receive a bolt 85which is adapted to close the open ends of the hook formations and toretain in the latter a rope loop 81.

With the tong suspended in pro-perbalance, the jaws are opened to theirwidest extent, as shown in Fig. 3, in order to receive the pipe to beturned, as indicated by phantom lines 880:. The jaws 56 and 64 arepreferably free pivoting and may be swung by gravity to open positionmerely by tilting the tong. The operator, standing on the side of thehandle 20 from which the jaw 56 projects, may now conveniently grasp thehandle M with his right hand and move the tong toward the pipe until thejaw 56 comes into contact therewith,

as indicated by dotted lines 8%. Now, by forcing forwardly on the handleEl with his right hand and with the left hand simultaneously pushing thehandle 66 in leftward direction, the jaws 2d and 64 are rotated towardeach other and the lug 68 is brought into engagement with the crosspiece 39 of the latch 36 with a camming effect so that the latter ismoved outwardly and then snaps automatically behind. the lug due to theaction of the springs 42 and 43. Behind the face 63a, the

lug is rounded away in order that the mentioned camming effect may besmoothly accomplished.

It will be recognized, of course, that an operator, standing adjacentthe lug 13, may readily move the tong so as to bring the pipe engagingmeans represented by the dies 33 and 34 both into engagement with therear face of the pipe, after which a pressure applied leftward to thehandle 66 will havethe effect of throwing the jaws 56 and 61 into closedposition around the plpe.

The foregoing is an important feature of the invention, since it enablesa single operator to handle the tong. All of the parts which he mustmove in handling or operating the tong are within his grasp or reachwithout it being necessary for him to move from his position adjacentthe lug 13. The jaw means represented by the long jaw 24 has littlemovement relatively to the handle 2B, and, in fact, when the tong isopened, as shown in Fig. 3, the rear jaw means 24 has a fixed relationto the handle 20 b reason of the fact that the spring 59 holds the stoplug against the stop lug 21. Therefore, the positioning and movement ofthe rear jaw means is accomplished by movement of the handle 28, andmovement of the front jaw means, consisting of the jaws 56 and 61, isaccomplished through force applied to the handle 66. This control of themovement of the rear jaw means by movement of a handle 20 makes possiblethe hereinbefore set forth ease of operation of the tong by a singleoperator, since he is able to control the rear jaw means throughmovement applied to the handle, while the front jaw means is controlledby the handle 66.

The latch face 39a is flat and to compensate for springing of the metalin the lug jaw 54 when under heavy stress, is so disposed that its inneredge is nearer pintle 4| than its outer edge, and the lug face 68a iscomplementarily inclined. Due to this undercut arrangement of thesecooperating faces, when the inner edge of the face 39a passes theoutside top of the latch lu the latch is free for an instant so that thelatch springs have an opportunity tocompletely close the latch. Thus thedanger ofthrowing'a heavy strain on the tong with the latch partlyclosed is avoided. The tong is either completely latched, or not latchedat all and once engaged, the faces cannot become accidentally disengagedwhile the tong is under load. By the same token, it is necessary toswing the handle 26) in counterclockwise direction in order to relieveclosing pressure of the jaws in order to release the latch from the lug.Any extreme inward movement of the latch such as would impair or destroythe locking effect is prevented by the stop 41. The lug has its lateraledges beveled, as heretofore mentioned, so that it will always beproperly guided to latching position, even though the pivot holes areworn so as to prevent the jaws from lining up with Original precision.

With the jaws operatively linked about the pipe, the handle is pulled sothat the pivot 25 is swung in a clockwise direction relative to thepivot 51, thereb moving the jaws into engagement with the pipe. As tothe jaws 24 and 56, their engagement with the pipe is through the dieswith which their faces are equipped. The pipe is preferably directlyengaged by the curved face of the jaw 64, which exert a force inward asindicated by the arrow 7' of Fig. 12 to react against the forces 2' andWith the two die-containing jaws permanent in the tong through allsizes, and the lug jaw only being replaceable to fit work of widelyvarying circumferences, the best combination of curvaturefitting-isobtained. With the die-containing jaws only the sharp ridges of the diescontact the pipe--ridges that are necessary to make the tong grip; hencethe jaws that must work with the greatest range of sizes do not contactthe work through a face, but through the relatively sharp projections orridges of the dies. This eliminates the dimculty of attempting to have aface which is cut for the largest pipe size attempting to fit thesmallest diameter pipe. The only jaws that approximate the curvature ofthe pipe are the lug jaws, and the full range of the tong is dividedamong three or more of these lug jaws.

As here shown. the common plane of the axes of pintles 25 and 5'! is atabout a 35 angle with the longitudinal medial line of the handle, and Ifind that this disposition is highly effective in assuring a powerfulcontracting action of the jaws. While the angle referred to ispreferably about 35, it desirably should not be less than 20, or morethan When the jaws are engaged with a work piece of the relative sizeshown at 88 in Fig. 1 and a lug jaw of the relative size shown in thatfigure is used, and the common plane of pintles 25 and. '51 intersectsthe axis of the work piece. the pintles M, 58 and 5! are substantiallyequi-angularly spaced at about The evident superiority of my new tongresults from a proportioning of the jaws and the placing of the pivotsso that there is not a great difference in the shearing stress appliedto these pivots. thereby making it possible to use pivot pins which areall of the same diameter and use of these pins under conditions whereinone or more of the. pins are not liable to failure due to excessiveforce applied as the result of unbalance of levers formed by the jawsconnected by the pins. A distinguishing characteristic of my new tong isthe placing of thepins so that they lie on a spiral S, Fig. 12,generated around the center of the'pipejso that itsinner end starts withthe'center of the fulcrum pin 51 and its outer end passes through thecenter of the working pin j25. Accordingly, this spiral S has its innerend has a length between the centers of its pivots 4| and 25 which isgreater than twice the diameterlof the pipe 88. This proportioning ofthe long jaw 24 with respect to the diameter of the pipe places thepivot 4| at a considerable distance to the left of the line a-l-a, Fig,12, which passes through the centers of the Pin 58 and the held pipe 88,intermediate the lateral extremities of the die means 33 and 34 andpreferably substantially centrally between these die means 33 and 34.Also, the die means 33 and 34 are dis posed so as to lie close to theline cc which passes through the centers of the pins 4! and 51 and isapproximately tangential to the wall of the pipe 88 at the point wherethe line a-ain tersects the pipe 88 proximate to the dies 33 and 3d.When force is applied to the tong handle in clockwise direction, aclosing force will be appliedto the'rightward end of the long jaw toswing the long jaw 24 in clockwise direction on .the outer pin 5!,thereby moving the dies 33 and 34 toward'the pipe in the radialdirection indicated by the arrows z. A similar condition exists withrelation to the dies 60 and SI of the short 'jaw for the reason thatthese dies substantially coincide with the line b- -b which issubstantially tangentialto the wall of the pipe 88, and which passesthrough the centers of the pins 51 and 58, the result being that whenthe short jaw 56 is swung in clockwise direction around the pivot 58,the dies 60 and BI will move radially inward, as indicated by the arrow70, as engagement of the dies 60 and SI with the surface'of the pipe ismade. Also, the face of the lug jaw 64 which engages the surface of thepipe 88 substantially coincides with the line dd which is tangential tothe pipe wall 88 and passes through the centers of the pivots ll and 53.Further characteristic conditions of the applican-ts device are that theline m m which passes through the center of the held pipe 88 andintermediate the lateral extremities of the dies 6lland 6| issubstantiallyperpendicular to the line b-b, and that the line n-n whichpasses through the center-of the held pipe and through the center of thefulcrum pivot pin'51 is per- 'pendioular to. the line dd and intersectsthis line dd at substantially the center thereof.

Furthermore, it will be perceived that the lines 12-2), 0-0, and 09-11define a substantially equilateral triangle, having at its corners thefulcrum pin 51 and the outer pivot pins 4! and 58.

By the described characteristic placing of the pivot pins li 51 and 58,I provide a tong in which I assure substantially even distribution ofstressamong all the pivot pins and I assure that no pivot pin hassubstantially less stress than the fulcrum pivot pin or substantiallygreater stress than the work' pivot pin. The characteristic placing ofthepins results in substantially an even stress on the pins, equalstress of jaws against the work, the pressure of the jaws against thepipe equally spaced around the pipe, andallows the handle ends of thelong and shortjaws to remain in circular alignment over much wider swingof the handle 20 than any previous tong, thus making the tong cover awider range than any previous tong. r

In addition to the foregoing, the dies 33, 34, 60, and 6| move radiallyas they engage the pipe and therefore the dies have no sliding, shearing, or carifying'effect upon the surface of the pipe as the resultof tangential movement of the jaws as they engage the surface of thepipe, a condition found in a number of prior art tongs; It will beperceived that the'radial inward movement of the dies as they engage thepipe results in minimum wear on the dies, for the reason that tangentialstresses are not applied to the knife edges of the dies until they arefirmly seated in the surface of the pipe and rotational torque istransmitted from the tong to the pipe. .A special feature of myinvention is the provision of a practical and efiicient tong assembly 7which may be used with a wide range of pipe sizes, thereby reducing thenumber of pipe tongs which must be kept around a derrick, or which mustbe available. I provide a basic tong unit consisting of a handle, afirst jaw and a second jaw pivotally connected to the handle incooperative relation, and a complement or group of third jaws 64, 66a,and 64b, each of a different size and each being adapted to beseparately employed with the basic'tong unit. These links 64, 64a, and64b may be referred to as the replaceable adaptor links of the device,since,'by their use, they adapt the tong for a different range of sizes.

The substitution of one adaptor jaw for another is readily accomplishedby removal of the outer n pivot pin 58 so that the adaptor jaw then inuse may be replaced bythe selected adaptor jaw, which will be held inoperative position by the reinserted pivot pin'58.

The rope attachment means constituted by the hook formations 84 and 85at the power end of the handle are preferably made integral with thelatter and, as before stated, the bolt 86, serves to hold the rope inplace. This rope attachment means has several advantages over typesheretofore used. 'The rope is applied to the tong in such a way as topull on the handle between the horizontal extensions of the hookformations, and is positively held in place by the bolt 86 In attachareno loose parts other than this bolt. A rope may be applied to pull ineither or both directions as is often the case in actual practice.Should the tong be pulled around to such a position that the tong handleis in line with the line of pull, the rope is still pulling on the solidmetal of the handle.

I claim as my invention:

1. A tong'for gripping a pipe, comprising:' a handle having at one endthereof a working pivot and a fulcrum pivot; a long jaw connected tosaid working pivot and having an outer pivot and pipe engaging die meanssubstantially coinciding with the central portion of a lin which passesthrough said fulcrum pivot and said outer pivot when the tong is closedaround the pipe whereby inward swingingof said jaw on said outer pivotwill move said die means into engagement with which lies on a linepassing through said ful-' crum pivot and being substantially tangentialto the outer face of the held pipe, said last named line being disposedat substantially an angle of 60 from said first named line; and jaw andlatch means to connect said. outer pivots. a

2. A tong for gripping a pipe, comprising; a handle having at one endthereof a working pivot and a fulcrum pivot; a long'jaw connected tosaid working pivot and having an outer pivot and pipe.

the held pipe and on a line which passes through the center of said pipeand substantially the central portion of said die means; die meanscarried by said short jaw in a position to coincide with the centralportion of said line which extends through said fulcrum pivot and thepivot at the outer end of said short jaw; and jaw and latch means toconnect said outer pivots.

3. A tong including at least three work encircling jaws, latch means tohold said jaws in a position to encircle the work, a handle, and aseries of pivot pins including a work pivot pin, a fulcrum pivot pin onsaid handle, and interconnecting pivot pins carried by said jaws, all ofsaid pivot pins lying in a spiral which begins at the fulcrum pivot pin,progresses by operative connectionsthrough all of the jaws and ends atthe work pivot pin, said pivot pins being progressively more distantfrom the center of the encircled work from the said beginning to thesaid end of said spiral,

4. A three-jaw tong including three work en-, circling jaws, latch meansto hold said jaws closed around the work, a handle, and a series ofpivot pins including a work pivot pin, a fulcrum pivot pin on saidhandle, and interconnecting pivot pins carried by said jaws, all of saidpivot pins lying in a spiral, the inner end of which begins at thefulcrum pivot pin, progresses by operative connections through all ofthe jaws, and ends at the work pivot pin.

5. A tong unit of the character described, for use with any one of a setof complemental lug jaws of different sizes to produce a three jaw tong,comprising: a handle having at the front end thereof a work pivot meansand a fulcrum pivot means in spaced relation; a first jaw swingable onsaid work pivot means when said tong is closed around a pipe and havingfirst outer pivot means disposed at its outer end, said first jaw havinga pipe engaging element positioned substantially on a line extendingthrough said fulcrum means and said first outer pivot means when saidtong is closed around a pipe; a second jaw swingable on said fulcrumpivot means and having a second outer pivot means at its outer end, saidsecond jaw having a pipe engaging element positioned substantially on aline extending through said fulcrum pivot means and said second outerpivot means; and a latch member connected to said first outer pivotmeans for latching engagement with a selected one of said lug jaws, saidsecond outer pivot means being adapted for connection to an end of aselected one of said lug aws.

' 6. A tong unit of the character described, for" use with any one of aset of complemental lug jaws of different sizes to produce a three jawtong, comprising: a handle having at the front end thereof a work pivotmeans and a fulcrum pivot means in spaced relation; a first jawswingable on said work pivot means when said tong is closed around apipe and having first outer pivot means disposed at its outer end, saidfirst jaw having a pipe engaging element positioned substantially onaline extending through said fulcrum means and said first outer pivotmeans when said tong is closed around a pipe; a second jaw swingable onsaid. fulcrumpivot means andhaving a second outerpivot means at itsouter end, said second jaw having a pipe engaging element positionedsubstantially on a line extending through 'said fulcrum pivot means andsaid second outer pivot means; and a latch member connected to one ofsaid outer pivot means for latching engagement with a selected one ofsaid lug jaws, the other of said pivot means being adapted forconnection to an end of a selected one of said lug jaws.

7. A tong including work encircling jaws, a handle, and a series ofpivot pins including a work pivot pin and a fulcrum pivot pin on saidhandle, all of said pivot pins lying in a spiral which begins at thefulcrum pivot pin, progresses by 0perative connections through all ofthe jaws and ends at the work pivot pin, said pivot pins beingprogressively more distant from the center of the encircled work fromthe said beginning to the said end of said spiral.

8. A tong including work encircling jaws, a ban dle, and a series ofpivot pins including a work pivot pin and a fulcrum pivot pin on saidhandle, all of said pivot pins lying in a spiral which begins at thefulcrum pivot pin, progresses by operative connections through all ofthe jaws, and ends at the work pivot pin.

9. A tong including work encircling jaws, a handle, and a series ofpivot pins forming operative connections through all of said jaws andsaid handle and including a work pivot pin and a fulcrum pivot pin onsaid handle, said pivot pins, beginning with said fulcrum pivot pin andprogressing by operative connections through all of said jaws to saidwork pivot pin, being positioned progressively greater distances fromthe center of the encircled work.

10. A tong comprising work encircling jaws, including a long jaw and ashort jaw, a handle, and a series of pivot pins forming operativeconnections through all of said jaws and said handle, and including awork pivot pin pivoting said long jaw to said handle, and a fulcrumpivot pin pivoting said short jaw to said handle, said pivot pins,beginning with said fulcrum pivot pin and progressing by operativeconnections through all of said jaws to said work pivot pin, beingpositioned progressively greater distances from the center of theencircled work.

11. A tong including work encircling jaws, a handle, and a series ofpivot pins forming operative connections through all of said jaws andsaid handle and including a work pivot pin and a fulcrum pivot pin onsaid handle, said pivot pins, beginning with said fulcrum pivot pin andprogressing by operative connections through all of said jaws to saidwork pivot pin, being positioned progressively greater distances fromthe center of the encircled work, adjacent ends of a pair of said workencircling jaws being releasably secured together by latching meanscomprising a latch pivoted to one of the jaws of said pair 11 and a lugon the other law of said pair, s aid latch having a lug engagingfaceinclined inwardly and toward the pivoting axis of the latch and saidlug having a latch engaging face inclined complementarily to said lugengaging face of said latch. V 7 V g 12. A tong unit of the characterdescribed for use with any one of a set of complemental lug fulcrummeans and said first outer pivot means jaws of different sizes toproduce a three jawtong, comprising: a handle having at the front endthereof a work pivot means and a fulcrum pivot means in spaced relation;a first jaw swingable on saidwork pivot means when said tong is closedaround aypipe and having first outer pivot means disposedat its outerend, said first jaw having a pipe engaging element positionedsubstantially on a line extending through 'said when said tong is closedaround a pipe, and pro-V jecting within the space defined by said lineand a line which extends through said work pivot means and said firstouter pivot'means; a second jaw swingable on said fulcrum pivot meansand having a second outer-pivot meansat its outer,

,ingengagement with a selected one of said lug jaws, said second outerpivotmeans being adapted for connection to an end of a selected one ofsaid lug jaws.

WILLIAM W. WILSON.

